6 AWG Wire Ampacity — How Many Amps Can 6 Gauge Handle?

6 AWG wire—whether copper or aluminum—is the go-to conductor for 50–60 A sub-panels, electric ranges, cooktops, EV chargers, and some split-system HVAC units. Copper 6 AWG hits the sweet spot between cost, flexibility, and ampacity, and it’s widely stocked in THHN/THWN-2, XHHW-2, NM-B, and USE-2 variants. Aluminum 6 AWG, while carrying about 5–10 A less than its copper counterpart, is a budget-friendly alternative that’s common in XHHW-2, SER, and USE-2 cable for feeder runs where weight and price matter more than bend radius. This post answers questions about ampacity as it relates specifically to 6-gauge wire.

Quick answer:

• Copper 6 AWG safely carries 55 A (60 °C), 65 A (75 °C) or 75 A (90 °C) under standard NEC conditions.

• Aluminum 6 AWG carries 50 A (75 °C) or 55 A (90 °C).

• In most residential and light-commercial installs this pairs with a 50 A or 60 A breaker, depending on the equipment listing and local code.

Looking for the deeper “why”? See our Ultimate Guide to Wire Ampacity & NEC Basics for the full theory behind temperature ratings, derating, and terminal limits.

Ampacity at a Glance

* See NEC Table 310.16 for full chart.
† Not more than three current-carrying conductors in raceway or cable, 30 °C ambient.
‡ Often limited to 75 °C (65 A) by termination lugs.

Key Variables That Can Change Those Numbers

1. Insulation & Temp Rating – NM-B is capped at 60 °C; THHN/THWN-2 can use the 90 °C column, but the breaker lugs may only be 75 °C.
2. Ambient Heat & Conduit Fill – Temperatures > 30 °C / 86 °F or more than three conductors in the same raceway trigger NEC derating (see Table 310.15(B)(3)(a)).
3. Terminal Ratings – The weakest link (often 75 °C lugs) sets the real-world ampacity.
4. Copper vs. Aluminum – Aluminum’s lower conductivity means ~10 A less capacity at the same gauge.
5. Voltage Drop – Long runs (≈ 100 ft +) may force you to upsize to 4 AWG to keep ≤ 3 % drop.
   
   

Common 6 AWG Use-Cases & Breaker Pairings

Always confirm with NEC 240.4 and the equipment listing before finalizing OCPD sizing.

Mini Derating Example

Scenario: Four current-carrying THHN conductors (hot A, hot B, neutral, ground) in a conduit running through a 40 °C attic.

1. Base ampacity (6 AWG copper THHN) – 75 A (90 °C column).
2. Adjustment for > 3 conductors – 80 % factor → 75 A × 0.80 = 60 A.
3. Ambient > 30 °C – 88 % factor (from Table 310.15(B)(2)(a)) → 60 A × 0.88 ≈ 53 A.
4. Result: You’d need to protect the conductors at ≤ 53 A, so a standard 50 A breaker would be code-compliant, or you’d upsize the wire to 4 AWG to keep a 60 A breaker. (Full math in the pillar guide.)

Frequently Asked Questions

Can I land 6 AWG copper on a 60 A breaker?
Yes—when installed under standard conditions and within 75 °C terminations, 6 AWG copper’s adjusted ampacity typically covers a 60 A OCPD. Always run the derating math for your exact environment.

When should I jump to 4 AWG?
If your run exceeds ~100–150 ft, or the load is a constant 58–60 A, upsizing mitigates voltage drop and leaves headroom for future expansion.

Does THHN in conduit always get the 90 °C rating?
Only if every termination on the circuit is rated 90 °C—a rarity in residential gear. Most breakers and panelboards are 75 °C max, so 65 A is the practical ceiling.

Conclusion & Next Steps

• Rule-of-thumb: 6 AWG copper ≈ 55–65 A (75 °C) and pairs nicely with a 60 A breaker; aluminum tops out ~50 A.
• Check the variables—insulation class, ambient temp, conduit fill, and lug ratings—before locking in your breaker size.
• Need a refresher on derating or NEC tables? Jump back to our Ultimate Guide to Wire Ampacity.

Still unsure? Always consult a licensed electrician and your local AHJ.